It’s been 4 years since I did my little review on Camping In Taiwan’s butane refill tool, so I think we’re about due for a follow up. This revisit isn’t so much about the tool, but about the durability of the canisters themselves: are they safe to refill? What about rust? Will they eventually rupture? The TL;DR answer is that canisters are sufficiently over-designed to allow numerous refills and even some degree of overfilling.
As a kind of proof, here is my 5-year-old MSR IsoButane canister, refilled 30+ times, and still going strong:
A note, that some low-quality butane fuels did cause some flecks and orange-coloured flames temporarily when using the canister in inverted mode with another stove. These seem to depend entirely on the quality of your refills (cheaper fuel = potentially more impurities). When using the canister in normal, upright mode (pictured), the flames always register clear and blue.
I have not noticed any rattling or structural integrity issues of the canister either – moisture contamination, if it is happening, doesn’t seem to be a large concern. The more important factor than stress from refilling is wear and tear on the fitting’s seal – a few times during cold weather, the valve has stuck open when removing the stove (oops!). It closed itself again after a few seconds, but considering these canisters aren’t meant to last forever, I would look at the seal as the likeliest point of failure. I will likely retire the canister if (when) the sticking issue gets worse.
Over the course of my summer and fall hiking and camping, I have consumed at least 12 225g bayonet-style cylinders refilling the MSR canister. That’s about 24 full refills, though in reality I did many more partial refills. I manage to get my refills for about $1 each, which means over the course of the 4 years, I’ve spend $12 on fuel. Comparable 225g IsoButane canisters go for about $7.25, meaning I saved myself $75 on fuel over 4 years! The refill tool has certainly paid for itself!
And the stove using the refilled canister still makes coffee just fine, too!